Two CORBA implementations (IONA Orbix and Digital ObjectBroker)
were selected and evaluated in the 2nd half of 1995, for applications
to the context of Environmental Information Systems.
Orbix was found slightly faster.
Some selection criteria, and the fact that new versions have
already been delivered (including of the CORBA specification)
relativise the interest of the results.
This application is moving to WWW and Java.
GOODE is an project aiming at building tools using CORBA's DII and
Interface Repository. Two tools have been produced: CorbaScript, a
scripting language for accessing CORBA objects, and CorbaWeb, allowing
their access through standard Web browsers.
This addresses only the aspect of accessibility/availability of
distribution, and is restricted to a pure client/server model, i.e. to
shallow distribution.
Obviously the same presentation was made at COOTS96 in Toronto, in
June 96 (see the report by Petri Nuuttila, from NRC).
There exists several competing similar products (e.g. DIIShell,
TclDII). This one is available
for free.
I was indicated a related paper by Peter Wegner on temporal scopes
(not confirmed yet), as well as a relation with the concept of
futures in the BETA system.
I had also questions on synchronisation.
This presented a model of distributed programming, based on the
generic separation of configuration,
synchronisation, and functional descriptions.
I got the impression that such an approach would lead to the
spreading of information into the separate hierarchies, with a lot of
coupling.
This project aims at extending the Oberon system to support
distribution, with interface descriptions being generated dynamically
from the code.
Currently, data structures are deep copied.
The garbage collection system is also extended to support
distribution.
This project works on a restricted approach to distribution: it
selects algorithms to manipulate distributed sets of objects.
The language chosen as basis is Modula-3.
This project focuses on a configuration language allowing the
distribution of large-grained components (legacy systems).
The middleware of use is Xerox ILU.
This was the most interesting presentation of the workshop (related to a paper in the conference). It considered two approaches to add support for Group Communication to CORBA.
These were the integration of a system providing group communication into the ORB (thus modifying this one), and the provision of a new CORBA service.
The first approach has been taken by commercial products (Electra, Isis). It offers transparency at two costs: portability and a change in the semantics of CORBA (since object references do not uniquely identify singleton objects).
The second is more modular, and in the spirit of CORBA, but requires the use of smart proxies to access the objects.
The last presentation reported the use of CORBA is a simulation system of the atmospheric pollution of the town of Stuttgart.